1 files changed, 46 insertions, 0 deletions
diff --git a/include/llvm/Transforms/IPO/GlobalDCE.h b/include/llvm/Transforms/IPO/GlobalDCE.h
new file mode 100644
index 000000000000..57e174c2a37f
--- /dev/null
+++ b/include/llvm/Transforms/IPO/GlobalDCE.h
@@ -0,0 +1,46 @@
+//===-- GlobalDCE.h - DCE unreachable internal functions ------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This transform is designed to eliminate unreachable internal globals from the
+// program.  It uses an aggressive algorithm, searching out globals that are
+// known to be alive.  After it finds all of the globals which are needed, it
+// deletes whatever is left over.  This allows it to delete recursive chunks of
+// the program which are unreachable.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_TRANSFORMS_IPO_GLOBALDCE_H
+#define LLVM_TRANSFORMS_IPO_GLOBALDCE_H
+
+#include "llvm/IR/Module.h"
+#include "llvm/IR/PassManager.h"
+#include <unordered_map>
+
+namespace llvm {
+
+/// Pass to remove unused function declarations.
+class GlobalDCEPass : public PassInfoMixin<GlobalDCEPass> {
+public:
+  PreservedAnalyses run(Module &M, ModuleAnalysisManager &);
+
+private:
+  SmallPtrSet<GlobalValue*, 32> AliveGlobals;
+  SmallPtrSet<Constant *, 8> SeenConstants;
+  std::unordered_multimap<Comdat *, GlobalValue *> ComdatMembers;
+
+  /// Mark the specific global value as needed, and
+  /// recursively mark anything that it uses as also needed.
+  void GlobalIsNeeded(GlobalValue *GV);
+  void MarkUsedGlobalsAsNeeded(Constant *C);
+  bool RemoveUnusedGlobalValue(GlobalValue &GV);
+};
+
+}
+
+#endif // LLVM_TRANSFORMS_IPO_GLOBALDCE_H